Add support for parameter attributes (#48)

* 1

* 2

* 3

* .

* x

src/ProxyInterfaceSourceGenerator/Builders/MethodParameterBuilder.cs

@@ -0,0 +1,25 @@
+using System.Text;
+using Microsoft.CodeAnalysis;
+using ProxyInterfaceSourceGenerator.Extensions;
+
+namespace ProxyInterfaceSourceGenerator.Builders;
+
+internal static class MethodParameterBuilder
+{
+    public static string Build(IParameterSymbol parameterSymbol, string? type)
+    {
+        var stringBuilder = new StringBuilder();
+        if (type is { })
+        {
+            stringBuilder.Append(parameterSymbol.GetAttributesPrefix()); // "" or [NotNullWhen(true)]
+            stringBuilder.Append(parameterSymbol.GetParamsPrefix()); // "" or "params "
+            stringBuilder.Append(parameterSymbol.GetRefPrefix()); // "" or "out "
+            stringBuilder.AppendFormat("{0} ", type); // string or another type
+        }
+        
+        stringBuilder.Append(parameterSymbol.GetSanitizedName()); // "s" or "i" or ...
+        stringBuilder.Append(parameterSymbol.GetDefaultValue()); // "" or the value
+
+        return stringBuilder.ToString();
+    }
+}